Author Archive

Posts by Ariel Weisberg 

Intro to VoltDB Command Logging

July 26th, 2011 in VoltDB Products
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VoltDB’s new command logging feature reduces the window of data loss during a cluster wide failure from single digit minutes (the window between snapshots) to zero. Command logging can be tuned to give you the same amazing latency and throughput you get from VoltDB, even on a single 7.2k SATA disk. Our unique approach to log based durability exploits the determinism and replication inherent in VoltDB’s architecture to avoid the overhead and latency of ARIES style logging.<--break->

How We Log

A command log is kept at every node and contains partially ordered stored procedure invocations. As stored procedure invocations arrive … Read more

 

Transaction Ordering and Replication

February 15th, 2011 in VoltDB Products
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Transaction Ordering and Safety

In this blog post I want to build on the example given by John and dig a little deeper into how VoltDB ensures global ordering and replication in the face of failures.

I am going to drill down on the following paragraph

Site 1 and site 4 both receive the message from the initiator. They then each do the same work in parallel. Since each individual site performs transactions one at a time, the transaction information is put into a queue at site 1 and queue at site 4. Work is pulled from the queues at

… Read more

 

Living the Asynchronous LifeStyle, or how I Learned to Stop Threading and Love the Non-Blocking Call [back]

July 14th, 2010 in VoltDB Products
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A 1:1 mapping between software threads and hardware threads is a core part of VoltDB’s approach to performance and also turns out to be the core of the asynchronous lifestyle. By multi-plexing work through a pool of threads appropriately sized for your hardware, you can obtain the maximum parallelism that your hardware can provide and efficiently process many discrete tasks (although parallelism != performance). In the VoltDB world, tasks tend to be very small in both size and duration, and there are thousands of them in flight at any given time in order to ensure that the execution pipeline never … Read more